tenpin-bowling-score.js

var getTenPinBowlingScore = function (result) {

  // construct the array from string
  var resultArr = result.split(',').map(s => {
    return parseInt(s)
  })

  var calculatedResult = resultArr.reduce((preVal, curVal, curIdx, arr) => {

    // calcualte any extra score
    if (preVal.extraCounts) {
      preVal.currentFrameScore += (curVal * preVal.extraCounts.length)
      preVal.extraCounts = preVal.extraCounts.map(c => {
        return c - 1
      }).filter(c => {
        return c > 0
      })
    }

    // determine the frame
    if (preVal.isNewFrame) {
      preVal.tempFrameCount++

      // add a new frame
      preVal.tempFrameCount <= 10 && preVal.frames.push([])

      // strike: extra score for next 2 falls
      preVal.isNewFrame = (curVal == 10 && preVal.tempFrameCount <= 10)
      preVal.isNewFrame && preVal.extraCounts.push(2)
    } else {
      preVal.isNewFrame = true
      // spare: extra score for next fall
      curVal + arr[curIdx - 1] == 10 && preVal.extraCounts.push(1)
    }

    preVal.currentFrameScore += curVal
    preVal.frames[preVal.frames.length - 1].push(curVal)

    // add the frame score to the total score
    if (preVal.isNewFrame || (curIdx == arr.length - 1)) {
      preVal.totalScore += Math.min(30, preVal.currentFrameScore)
      preVal.currentFrameScore = 0
    }

    return preVal
  }, {
    totalScore: 0,
    currentFrameScore: 0,
    isNewFrame: true,
    tempFrameCount: 0,
    frames: [],
    extraCounts: []
  })

  console.log("Frames for %s\nis %s", result, JSON.stringify(calculatedResult.frames))

  return calculatedResult.totalScore
}

var test = function (test, expected) {
  console.log("Testing %d, expecting %d", test, expected)
  console.log((test === expected ? "Passed" : "Failed") + "\n")
}

test(getTenPinBowlingScore('10,10,10,10,10,10,10,10,10,10,10,10'), 300)
test(getTenPinBowlingScore('1,2,3,4,5,5'), 20)
test(getTenPinBowlingScore('9,1,10,8,0,2'), 48)
test(getTenPinBowlingScore('10,0,0,9,1,0,0,8,2,0,0,7,3,0,0,6,4,0,0'), 50)

Expected result:

Frames for 10,10,10,10,10,10,10,10,10,10,10,10
is [[10],[10],[10],[10],[10],[10],[10],[10],[10],[10,10,10]]
Testing 300, expecting 300
Passed

Frames for 1,2,3,4,5,5
is [[1,2],[3,4],[5,5]]
Testing 20, expecting 20
Passed

Frames for 9,1,10,8,0,2
is [[9,1],[10],[8,0],[2]]
Testing 48, expecting 48
Passed

Frames for 10,0,0,9,1,0,0,8,2,0,0,7,3,0,0,6,4,0,0
is [[10],[0,0],[9,1],[0,0],[8,2],[0,0],[7,3],[0,0],[6,4],[0,0]]
Testing 50, expecting 50
Passed

Tested with Node v6.1.0